Valve for engines.



E. H4 ALLFREE.

VALVE FOR ENGINES.

APPLICATION FILED MAR.18,1912,

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E. H. ALLFREE.

VALVEFOR ENGINES.

APPLICATION FILED MAR.18,1912.

15,93%039, Patented July 9, 191.2.

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E. H. ALLFRBE.

' VALVE POB. ENGINES.

APPLICATION FILED MAR.18.1912.

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LUSQS E. H. ALLFREE.

VALVE FOR ENGINES.

APPLICATION FILED MAR.18,1912.

Patented July 9, 1912.

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iinwiii H. ALnrnnn, or CHICAGO, ILLINos.

VALVE FOR ENGINES.

S'pecicaton of Letters Patent.

Patented JulyQ?, 1912.

Application filed March 18, 1912. Serial No. 684,578.

My invention relates to improvements in valve constructions'of the type disclosed in United States Letters PatentA No. 770,671, granted to James B. Allfree, and involving, generally stated, a main valve-device for controlling the inlet of the fluid-pressure to the engine and the primary exhaust therefrom; and an auxiliary valve-device con-` compression-controlling' means,

f which'goperates to prolong the exhausting of tudinal sectional the engine-cylinder, my invention constituting improvements in the construction disclosed in said patent. The valve mechanism of said patent whenforming the fluid-pressure control of an engine operated through the medium of superhea'ted steam, presents `the disadvantage of its movable parts warp. with the consequent result of rendering the valve device leaky and impairing its" ins,

functions and those of the engine.

My object is to provide a valve construction ofthe type above referred to which will be economical of manufacture, be capable of being readily and veconomically repaired inthe event of undue wear of the bearing surfaces of the valve-casings, and which will not present the disadvantage of. its warping, especially when incorporated in an engine another object is to provide for the minimum clearance in the exhaust passages between the cylinder and the points at which the valve closes the. exhaust, commensurate with the amount of clearance required to be present in order that theproper cushioning of the piston inits nal movements may be effected, Y

Referring tothe accompanying drawings-"Figure 1 is `a broken-view in longielevation Vof an engine.- cylinder equipped with valve mechanism of the type abovereferred to and embodying my improvements for controlling ,the 1ntroduction into. and exhaust` therefrom of the Huid-pressure for operating the piston therein, thesection being taken at the line 1 on Fig. 3, through the main valve ofthe engine, and viewed in the direction of the operated by superheated steam; andy arrow. Fig. 2 is a similar view taken at the line 2 on Fig. 4 and viewed in the direction of the arrow. Fig. 3 is a section taken at the line 3 on Fig. 1 and viewed in the direction of the arrow. Fig. 4 is a section taken at the line 4 on Fig. 1 and viewed in the direction of the arrow; and Fig. 5, a section taken at the irregular line 5 on Fig. 4 and viewedV in the direction of the arrow, the

main and auxiliary valves, as well .as the linings, or bushings, at one end of the steam-chest and `which coperate with the valves, being omitted,

As the construction illustrated is Aof the same general form and involves the same principle of bperation as the construction disclosed in said patent, a general description of the present construction, so far as t-he features disclosed in said patent are concerned, will suiiice. The cylinder of an engine is illustrated at 10 and is provided with the usual heads 11 and 12, the cylinder l containing a piston 13, the stem thereof operating in a stufling-box 14 in the head 11, the piston in practice being connected with the usual guided cross-head (not shown) as is the general practice in engine constructions. The ortion of the cylinder-casting which contains the main and auxiliary valve-devices for controlling the introduction of the steam into the cylinder and the exhaust 'therefrom is represented at 15, and contains a main-valve chamber 16 and an auxiliary, or compression-controlling, valve-chamber 17 which are laterally oset with relation to each other,as illustrated in Figs. 3 and 4, the chamber 16 between its end connecting with -a conduit 18 which has an inlet 19 through which the steam is introduced into the conduit 18 from the source of supply (not shown), and the chambers 16 and 17 having fitted into their opposite ends cylindrical sleeves, or bushings, 20 and 21, respectively. The casting 15 contains at its opposite ends ports 22 and 23 which open into the cylinder 10 at its opposite ends and inta the chambers 16 and 17 through o enings'.24 and 25, in the bushings 20 an ,21, respectively Y Q v The main valve which is in the chamber 16 and controls the introduction of steam into the cylinder 10 from the chamber 16,v for operating the piston iu said cylinder, and cont-rolling the opening and closing of the main exhaust of the cylinderV 10, is represented at 26. This valve in the preferred construction illustrated comprises a pair of cylindrical heads 27 and 28 rigidly connected together by a bar 29, the heads 27 ,and 28 posite ends ofthe cylinder 10 through the ,having sliding fit in the bushings 20,. The

As the chamber 16'is connected With the conduit 18 intermediate th-e heads 27 and 28 of the valve 26 t-he steam supplied to the conduit 18 is alternately discharged by the reciprocations of the valve 26 into the op"- ports 22 and 23 for driving the piston 13. The casting 15 at its opposite ends, beyond the ports 22 and 23 contains exhauststeam passages 34, the outlets of Which areY represented at the passages 34 being separated from the ports 22 and 23 by Walls 36, through openings 37 and 38 in which Walls the bushings 20 and 21, respectively,

. extend, the bushings 20, Which extend transversely across the passages 34, being providedabout their peripheries with openings 39 which register with said passages, and the bushings 21, having their outer ends open and in communication With the passages 34 as represented in Fig. 2.

In practice, thevalves 26 and 30 are connected at stems 261 .and 30*L thereon, withA valve-gear of any suitable'type, as tor example that illustrated in United States Letters Patent No. 1,002,112, for producing the properly timed operation of these valves relative to each other and to theypiston as set forth in said United States Letters'Patent No. 770,671,the valve 26 operating to introduce steam alternately into the opposite ends of the cylinder lO'for driving the piston 13 and exhausting the cylinder; and the valve 30, which has a lagging movement relative to the main valve 26, serving prolongthe exhausting of the cylinder 1() after the main exhaust closes, sufficient to reduce to the minimum the compression encountered by the p iston at theends'ofits strokes, the steam in these operations of the fvalve 26 passing from the chamber 16 through theports 22 and 23 alternately, into the cylinder 10, and the exhaust steam discharging through the ports 22 and .23, alternately, into -the bushings 20 and 21 through the openings 24 and 25,/respectively, therein, and thence through the openings 39 in the bushings 20, and the' open ends of the bushings 21,'into the passages 34, the .steamv thus exhausted discharging through the .outlets,35, it beingfunderstood that the steam in the cylinder 10, yWith eachj'- by Letters Patent, is

reciprocation of the piston 13 continues to exhaust therefrom until t-he compressioncontrolling valve closes the exhausts.`

In those constructions wherein a compression-controlling valve -is provided, the clearance `required between the valves andthe ends of the piston when at the limits of its strokes is Vof the minimum amount c omparedfwith those engines in .which such a valve is not employed, and the clearance should be so minimized las to insure the proper compressing of the steam left in the clearaneeto cushion the piston 13. In vieW of this condition the valve-devices may be placed closely adjacent to the cylinder and relatively short ports be provided, and furl thermore, in order that cylindrical pistonvalves be employed to the best advantage as. the fluid-pressure controlling means in av valve-device of the type to which this invention relates and the desired clearance be afforded, I so formthe ports 22 and 23 as to cause portions of their inclosing Walls to be brought into close proximity with the bushings 20 and 21 as 'represented at 40 and 41, Figu`4, the Walls 40 and41 containin grooves 42 and 43 registering With the open-v ings 24 and 25 in the bushlngs 20 and 21, whereby the steam in the ports 22 and 23 Ibears against the periphe'ries of the heads of the valves 26 and 30, equally 'in all directions and thus the valves/are balanced.

It will 'be readily understood from the foregoing that any axial movement of the valve-heads relative to each other as might occur when the valves are subjected tothe action of superheated steam, would have no impairing. effect upon the proper-operation of the valves as these heads would'. present the desired sliding tit regardless of vtheir axial adjustment 1n the coperating bushf ings. Furthermore, in the construction illustrated, .the valves 26 `and 30..are lnot only readily accessible and easily removed as units, from the valve-chambers, butin the event of undue Wear of any part of the' valve-chambers contacted with bythe lvalves in\their reciprocations, the ,same maybe readily remedied by reason ofthe provision of the here'inbeifore-describedv removable bushings in which the valves operate, which not only are inexpensive, but permit of ready substitutionof one for the other.

What I claim as'new and desire to secure In. a steam-engine, the combination of a cylinder, a single main-valve chamber communicating with a sourcepf steam supply, a l single auxlliary-.valve chamber, ports at opposite ends of said cylinder communicating with said chambers, exhaust-passages beyond said ports and separated therefrom by Walls containing o enings in alinement with said chambers, 'cy indrical bushings in said chambers andsaid openings communicating into said exhaust-passages,

Loews@ with said exhaust-'passages and containing openings about their peripheries communi- 'eating with said ports, a main ylindrical Valve in s aid main-valve chamber and operating in the bushings therein for controlling the admission of steam to said cylinders through said ports and exhaust of steam and a cylindrical compression-controlling valve in said auxiliary-valve chamber operating in the bushings therein and controlling the exhaust of steam therethrough into said exhaust-passages, said bushings being spaced throughout their peripheries from the Walls of said ports to cause'the steam pressure against said main and auxiliary valves, exerted through the openings inthe peripheries of said bushings, to be balanced, and portions of the Walls of said ports which extend transversely thereof, extending partially around and closely adjacent to said bushings for minimizing the clearance.

EDWIN H. ALLFREE. In presence of- J. G. ANDERSON,

0. C. AvIsUs. 

